About: http://webisa.webdatacommons.org/52119830

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Why not simply have some sort of indicator at the appropriate vendor that you already have purchased one or if you had already, simply receive an error message or some sort of a message that you can not purchase one right then and there!
http://www.w3.org/ns/prov#wasQuotedFrom	mmo-champion.com